Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context: it specifies that values are runtime-marked, merged in a specific precedence order, and scoped to the API key. This goes beyond the annotations by clarifying the data origin and hierarchy, which helps the agent interpret results correctly.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no fluff. The core functionality is front-loaded ('Key/value map of Vault items marked runtime'), followed by the merge order and endpoint. Every word earns its place, making it efficient and easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only GET with no parameters and no output schema, the description adequately conveys the return type (key/value map) and the merge precedence. It could mention value types or error cases, but these are minor gaps given the low complexity. Overall, an agent can confidently invoke this tool without needing additional detail.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema is empty with zero parameters, so the baseline is 4 as per the instructions. The description does not need to add parameter details since none exist. It also hints at the output shape (key/value map), which compensates for the lack of an output schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool returns a key/value map of Vault items marked runtime, and specifies the merge order (personal → Space → API key). It also provides the exact REST endpoint, leaving no ambiguity about the action and resource. Since there are no sibling vault tools, differentiation is unnecessary.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context about when this tool is relevant (retrieving runtime-permitted Vault values for the current credential) and the merge semantics. It doesn't explicitly state exclusions or alternatives, but with no vault siblings present, the need for such guidance is minimal. The context is sufficient for an agent to know this is the dedicated read path for runtime vault items.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.